efi: ia64: disable the capsule loader

EFI capsule loading is a feature that was introduced into EFI long after
its initial introduction on Itanium, and it is highly unlikely that IA64
systems are receiving firmware updates in the first place, let alone
using EFI capsules.

So let's disable capsule support altogether on IA64. This fixes a build
error on IA64 due to a recent change that added an unconditional
include of asm/efi.h, which IA64 does not provide.

While at it, tweak the make rules a bit so that the EFI capsule
component that is always builtin (even if the EFI capsule loader itself
is built as a module) is omitted for all architectures if the module is
not enabled in the build.

Cc: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/linux-efi/20201214152200.38353-1-ardb@kernel.orgSigned-off-by: Ard Biesheuvel <ardb@kernel.org>

drivers/firmware/efi/Kconfig

@@ -147,7 +147,7 @@ config EFI_BOOTLOADER_CONTROL
 
 config EFI_CAPSULE_LOADER
 	tristate "EFI capsule loader"
-	depends on EFI
+	depends on EFI && !IA64
 	help
 	  This option exposes a loader interface "/dev/efi_capsule_loader" for
 	  users to load EFI capsules. This driver requires working runtime

drivers/firmware/efi/Makefile

@@ -12,7 +12,10 @@ KASAN_SANITIZE_runtime-wrappers.o	:= n
 
 obj-$(CONFIG_ACPI_BGRT) 		+= efi-bgrt.o
 obj-$(CONFIG_EFI)			+= efi.o vars.o reboot.o memattr.o tpm.o
-obj-$(CONFIG_EFI)			+= capsule.o memmap.o
+obj-$(CONFIG_EFI)			+= memmap.o
+ifneq ($(CONFIG_EFI_CAPSULE_LOADER),)
+obj-$(CONFIG_EFI)			+= capsule.o
+endif
 obj-$(CONFIG_EFI_PARAMS_FROM_FDT)	+= fdtparams.o
 obj-$(CONFIG_EFI_VARS)			+= efivars.o
 obj-$(CONFIG_EFI_ESRT)			+= esrt.o

include/linux/efi.h

@@ -817,12 +817,6 @@ static inline bool efi_enabled(int feature)
 static inline void
 efi_reboot(enum reboot_mode reboot_mode, const char *__unused) {}
 
-static inline bool
-efi_capsule_pending(int *reset_type)
-{
-	return false;
-}
-
 static inline bool efi_soft_reserve_enabled(void)
 {
 	return false;
@@ -1038,6 +1032,7 @@ bool efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
 bool efivar_variable_is_removable(efi_guid_t vendor, const char *name,
 				  size_t len);
 
+#if IS_ENABLED(CONFIG_EFI_CAPSULE_LOADER)
 extern bool efi_capsule_pending(int *reset_type);
 
 extern int efi_capsule_supported(efi_guid_t guid, u32 flags,
@@ -1045,6 +1040,9 @@ extern int efi_capsule_supported(efi_guid_t guid, u32 flags,
 
 extern int efi_capsule_update(efi_capsule_header_t *capsule,
 			      phys_addr_t *pages);
+#else
+static inline bool efi_capsule_pending(int *reset_type) { return false; }
+#endif
 
 #ifdef CONFIG_EFI_RUNTIME_MAP
 int efi_runtime_map_init(struct kobject *);